CHRO 2009 in Japan. Summary of presentations of specific interest. Marjaana Hakkinen, Evira Elina Lahti, CRL

Transcription

1 CHRO 2009 in Japan. Summary of presentations of specific interest Marjaana Hakkinen, Evira Elina Lahti, CRL

2 New developments in quantitative risk assessment of campylobacteriosis (Havelaar, A. & Nauta, M.) Controlling campylobacteriosis in New Zealand: the role played by molecular epidemiology and modelling (French, N.P. & al.) Potentials for bacteriocin development to control Campylobacter in broilers (Svetoch, E. & Stern, N.J.) Vaccination of chickens agains Campylobacter as a potential intervention approach to reduce campylobacteriosis (Newell, D.G.)

3 Quantitative microbiological risk assessment of campylobacteriosis Most studies on risks associated with Campylobacter consider broiler meat Models available for all stages in the farm-to-fork chain Comparison of five models Detailed technical information available (

4 Conclusions from QMRA models for Campylobacter Rapid spread of campylobacters in broiler flocks within one week >95% of birds colonised On-farm monitoring may fail to detect Defeathering and evisceration lead to carcass contamination Cross-contamination in kitchen more important than undercooking Minced poultry meat is not considered

5 Conclusions from QMRA models for Campylobacter (continued) Heavily contaminated broiler carcasses contribute most to the human health risk >100-fold reduction of Campylobacter counts on carcasses significant risk reduction Different strategies to achieve the reduction in counts

6 Sources of uncertainty in current QMRA models Dose-response relationship Differences in virulence of Campylobacter strains Asymptomatic infections Protection due to acquired immunity

7 Campylobacteriosis in New Zealand Extraordinarily high incidence in humans In 2006: 383/ population 4-year concurrent sampling of human cases, food, environmental sources Source attribution studies: genotyping and new model-based analytical methods combined spatiotemporal modelling

8 Campylobacteriosis in New Zealand Estimated 58 to 74% of cases caused by poultry Predominantly in urban areas Environmental sources in minor role Important in rural areas where ruminantassociated cases were prevalent Important for children <10 y

9 Campylobacteriosis in New Zealand Application of control measures in poultry production Sharp decline in the incidence of human campylobacteriosis: In 2006: 383/ In 2007: 302/ In 2008: 157/

10 Bacteriocins for control of Campylobacter in chickens Non-toxic antimicrobial peptides produced by several bacterial species Paenibacillus polymyxa, Lactobacillus salivarius, enterococci Administration of purified, microencapsulated bacteriocins through drinking water or feed treatment over 3 d before slaughter 5 to 6 log reduction of caecal colonisation in pilot scale trials

11 Vaccination of chickens against Campylobacter Despite symptomless colonisation, campylobacters induce humoral and cellular immune responses in chickens Desired characteristics of vaccine easy to deliver acceptable not expensive

12 Live vaccines against Campylobacter Campylobacter organisms Additional competitive exclusion effect Vaccine strain must be eliminated before slaughter Salmonella vaccine strain expressing Campylobacter antigens Problems in reproducibility

13 Subunit vaccines against Campylobacter Flagellin antigens Lack of effective adjuvants DNA vaccines Problems in reproducibility

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